It is only in exceptional cases that somatic stimuli are the determining factor. Usually they coalesce completely with the symbolical expression of the unconscious dream content; in other words, they are used as a means of expression. Not infrequently the dreams show that there is a remarkable inner symbolical connection between an undoubted physical illness and a definite psychic problem, so that the physical disorder appears as a direct mimetic expression of the psychic situation.
“General Aspects of Dream Psychology” (1916). In CW 8: The Structure and Dynamics of the Psyche. pg. 502